Hong Kong stocks ended sharply lower on Thursday as US lawmakers struggled to hammer out a deal to avert a painful US debt default and Fitch warned it could downgrade the country's credit rating over the issue.

The Hang Seng Index tumbled 1.9 percent to finish 18,746.

The Shanghai Composite Index dipped 0.1 percent to 3,201, while the Shenzhen Composite Index on China's second exchange retreated 0.2 percent to close at 2,006.

Other Asian markets also fell, with Sydney, Seoul, Singapore, Manila, Mumbai, Bangkok and Jakarta all closing lower.

London, Paris and Frankfurt were also lower in early trade. (AFP)